1. Field of the Invention
The present invention relates to an electronic part to be used for various purposes, for example, such as dielectric antennas and coil parts and a method of manufacturing such electronic part, and more particularly to an electronic part using composite materials made up of synthetic resin and ceramic powder as a functional material and a method of manufacturing such electronic part.
2. Description of the Related Art
Ceramics and synthetic resin have been widely used as materials constituting electronic parts.
However, when ceramics is used, it was difficult to easily obtain electronic parts which are not uniform in shape because the electronic parts are formed by firing. For example, in Japanese Unexamined Utility Model Publication No. 5-55529, an electronic part made up of ceramics and having a three-dimensional form is shown. These use a sintered ceramic material in which a portion requiring plating is composed of a ceramic material having a catalytic action so that the portion is able to be plated and a portion not requiring plating is composed of a ceramic material not allowing plating. Therefore, even if a sintered material of a complicated three-dimensional shape is used, it is understood to be able to form electrodes in required portions by electroless plating without fail. Further, it is indicated that capacitors, etc. are able to be formed on a three-dimensional circuit board by making use of the dielectric constant of ceramics. However, because ceramics is used, complicated processes were required to realize the three-dimensional shape, and the dimensional overall accuracy of the three-dimensional electronic part thus obtained was not sufficient.
On the other hand, a method of manufacturing three-dimensional circuit boards using synthetic resin has been proposed. For example, Japanese Unexamined Patent Publication No. 63-128181 and Japanese Patent No. 2603828, disclose a method of obtaining three-dimensional circuit boards in such a way that a molded product is obtained through two molding processes by using resin containing a catalytic agent such as palladium so as to be plated and resin not allowing plating and on the molded product electrodes are formed by a photolithography or a common method of plating. By these methods, it is possible to obtain highly precise circuit boards of a three-dimensional shape as the synthetic resin is excellent in moldability. However, these three-dimensional circuit boards using the synthetic resin were used only to support conductive paths, and the electrical properties of the synthetic resin such as dielectric constant, permeability, etc. were not used in a positive way.
Further, Japanese Unexamined Patent Publication No. 3-4581, discloses a composite circuit of a board integrally formed by using composite resin materials of synthetic resin with ceramic powder dispersed therein. The board is composed of a first part made up of composite materials of resin with dielectric ceramic powder dispersed therein, and a second part made up of composite materials of resin with magnetic ceramic powder dispersed therein, that is, the board is constructed so as to have first and second parts which have electrical properties different from each other. The composite circuit is realized by first and second circuit elements which are composed of the first and second parts. However, the first and second circuit elements are only made up of the first and second parts, respectively.
That is, so far chip-type electronic parts making use of the electric properties and having easy moldability of synthetic resin has not been known.